Knoxfield house

From Greenlivingpedia, a wiki on green living, building and energy

Revision as of 11:00, 28 April 2007 by Peter Campbell (Talk | contribs)
Jump to: navigation, search

This house was designed to be as sustainable as possible on a small suburban block.It was built almost 5 years ago, and I moved in at the time of my retirement. Entry is via a curved slate path , along a wooden walkway representing a bridge over a dry water course, continuing on slate pavers surrounded by low ground cover of varieties of the herb Thyme.The garden has no lawn, uses Australian native s or plants with low water requirements mulched with coconut fibre.

The large wooden front door is protected by a curved roof, where chains are used instead of downpipes. An open plan living area and study/bedroom are located on one side, and 2bedrooms laundry and garage on the other. To the rear is a small Japanese courtyard.


The long axis of the house runs east - west enabling good solar access through the north facing windows in winter. External blinds made from Soltis fabric supplied by Ace of Shades protect the windows from the summer sun.
Thermal Mass
A concrete slab covered with tiles, give good thermal mass which retains the warmth of the winter sun during the day , and re radiates the heat at night thus reducing heating and energy use. There is less diurnal variation of temperature in an energy efficient house.
During hot periods in summer, the casement windows act like sails allowing the southern breezes to produce good cross ventilation and cooling. Condor vents have no moving parts, and work on the venturi principle.Hot air rises and can escape through these vents if required. The roof space is also vented.
The edge of the slab is insulated with polystyrene foam R1 ; walls apart from aerated concrete blocks insulated with wool/polyester batts R2 ; loose wool R3 in the ceiling; foil sizilation under the colourbond roof and tyvek reflective wrap for external stud walls in upstairs bedroom.
All windows are double glazed except the corner ones near the front door where comfort glass is used. The cedar frames do not conduct heat . Most of the windows are located on the north, north-east side with minimal ones facing west and south.
Embodied Energy /Recycled Products
Recycled components included reinforcing steel and slag ash ( a blast furnace byproduct) in the slab, posts in the living area and at the front door, merbu for front decking, jarrah for rear courtyard and bridge, victorian ash for stairs. Radial timber was used for the decking floor and fence, and salvaged timber for the decking posts.In the kitchen reconstituted granite for bench tops and New Age Veneers for cabinets was selected. The cement bricks for garage construction were seconds.
Water Efficiency
  • Rain water is collected via Smart Flow gutters and a first flush water diverter (Team Poly from Pakenham Tanks) in a 6000gallon ( 27,240L )tank.
  • This supplies all the household’s needs - the house is not connected to the mains water supply.
  • Water efficient appliances such as Asko front load washing machine and dishwasher , 3/6 L flushing toilets, AAA shower heads all minimise water use.
  • Grey water i.e. bathroom water and washing machine water is passed through an Aquablock Biofilter ( 2 cubic meters of biologically active peat , which destroys bacteria to Class A water standard). The treatment system is EPA approved. This water is stored in an underground tank, aerated, then used for toilet flushing and the garden. Kitchen and laundry trough water is not reused. Toilets are connected to the sewer.
  • Detergents. Only low sodium liquid detergents are used e.g. Trinature and Melrose products. Bar soaps and washing powders are avoided.
  • Statistics. Water use has been monitored with 2 Kent meters.
  • The water used in 3 years is equivalent to the annual amount used by the average Melbourne household.
  • In 2005 the house was self sufficient in water and saved 75% of the average householder’s discharge to the sewer.
Energy Efficiency / Photovoltaic Array
A solar hot water service - Edwards LX 305 -in series with a Bosch 22E continuous flow gas boost during the winter months, provides free hot water for about 7 months of the year.
Energy efficient appliances like the Bowin Lo Nox Gas space heater and general use of compact fluorescent light bulbs reduces gas and electricity use.
PV Array - 2.4kW Grid interactive system with a small battery bank.
32 X BP275 75W modules attached to the north facing roof at latitude angle i.e. 37 degrees, produce electricity when the sun is shining. Any electricity surplus to the needs of the house is exported to the grid during the day. At night when the sun does not shine , electricity is imported from the grid. The house has normal 240V wiring. At present the PV array is producing 55% of our electricity needs. The average Melbourne home consumes 6,265kWh per year. In 2005 only 1777kWh was imported from the grid i.e. a savings of 76% of average electricity use.


My house is modern, comfortable to live in, being warmer in winter and cooler in summer, collects the water that falls freely from the sky, and uses the sun’s power to produce 55% of electricity requirements thus reducing my ecological footprint and greenhouse gas (carbondioxide) emissions. Global warming is a serious threat to the future of mankind. We can all change our behaviour to minimise the problems. Every little bit can help make a difference. Let’s do it.


  • Owner: Lorraine Hughes
  • Sunpower Design Pty Ltd 03 9386 3700
  • Ace of Shades 03 9764 2260
  • Aqua Block Plumbing 03 9752 2209
  • Trinature Pty Ltd 02 4928 2199
  • RJM Sunpower Pty Ltd 03 9435 6376 (PV Array)
Personal tools